Optical inspection apparatus for use in inspecting potentiometer cards



J. I OPTICAL INSPECTION APPARATUS FOR USE IN Feb. 15, 1949. s, s'ru|INSPECTING POTENTIOMETER CARDS 2 Sheets-Sheet 1 Filed June '6, 1945 Feb.15, 1949. 2,461,939

J. S. STULL OPTICAL INSPECTION APPARATUS FOR USE IN INSPECTINGPOTENT-IOMETER CARDS Filed June 6, 1945 -2 Sheets-Sheet 2 I ,47' ORA E)Patented Feb. 15, 1949 LJNE'EED STATES PATENT QEFIQE OPTEGAL INSPECTIONAPPARATUS FOR USE IN INSPECTIN G POTENTIOMETER CARDS John S. Stull,Chicago, 111., assignor to Western Electric Company, Incorporated, NewYork, N. Y., a corporation of New York Application June 6, 1945, SerialNo. 597,768

in a predetermined path to guide successive por tions thereof under amicroscope Where the card may be inspected, the card being moved byactuation of the carrier through the manual rotation of a capstandrivingly connected to the carrier by a strand.

The invention will be more fully understood from the followingdescription taken in connection with the attached drawings, in whichFig. 1 is a plan view of the apparatus with parts shown in section;

2 is a detailed sectional view taken on the line 2-2 of Fig. 1;

Fig. 3 is a vertical cross sectional view taken along the line 3'3 ofFig. 1 with parts broken away;

Fig. 4 is an enlarged front elevational view of a portion of the deviceshowing a potentiometer card mounted on the apparatus;

Fig. 5 is a fragmentary vertical sectional View taken along the line5--5 of Fig. 4;

Fig. 6 is an enlarged fragmentary plan view of the potentiometer card,and

Fig. 7 is an enlarged fragmentary sectional view of the capstan.

The inspection apparatus is used for inspecting potentiometer cards IDor other elongated articles. The potentiometer cards vary in size andshape and consist of an elongated flat form or card I! of dielectricmaterial and predetermined outline having a straight top edge and uponwhich a fine wire [2 is closely wound. The convolutions of the wire l2are spaced apart from each other and the insulating coating surroundingthe wire is removed from a portion of the wire at the top edge of thepotentiometer card to bare the metallic wire and form a contactingsurface for engagement with the usual cooperating contact member, and itis this part of the potentiometer card that is inspected.

The inspection apparatus comprises a frame or carrier l5 in the shape ofa quadrant having an arc-shaped rim [1 and converging ribs l8 meeting toform an elongated vertical hub 19. The carrier is mounted for pivotalmovement on a shaft or pin which passes through an aperture 2! in thehub l9 and which is secured in apertures 23 and 24, respectively, of abase member-25 and a bracket 28 mounted on the base. A pair ofantifriction bearings 28 and 29 are provided inthe hub l9 and cooperatewith members 30 and 3|, respectively, to rotatably support the carrieron the shaft 28 A look nut 32 engaging the upper' threaded portion ofthe shaft 2o cooperates with the member 30 also threadedly engaging theshaft 29 to maintain the member 30 in position. To

retard the rotation of the carrier l5, a pair of brake members 35 and36, slidably mounted in the bracket 28, are urged against the outercylindrical surface of the hub I!) by a leaf spring 3! carried by thebracket 26. The rim ll of the carrier is raised to form a cardsupporting surface 4%, against which the potentiometer card is clampedbya plurality of clamps 4i spaced apart 'bers 47 which engage the threadedapertures 48 in the jaws 42. The members 41 ma be turned to rock themembers 42 about the; pins 44 and thereby move the upper ends of thejaws42 open against the action of bowed leaf springs 49 interposed betweenthe jaws 42 and the arms of the U-shaped brackets 45. Upon movement ofthe member M in the opposite direction to a' point where the head of themember 4'! is disengaged I from the U-shaped brackets, the jaw 42 willbe closed by the action of the spring 49 which will apply a uniformpressure thereto to clamp the card against the surface 40 of the rim H.

To accurately position the potentiometer card I. so that its top edge isin a horizontal plane a gage 'in the form of a fiat member 5!, having anarcuate edge, is mounted on the carrier l5. The gage Si is provided withparallel slots 55, through which pass securing studs 56. The gage member.1 55 is adapted to be moved forward to overlie and project beyond therim I! in which position the potentiometer card may be moved upward intoengagement therewith while the potentiometer card is being applied tothe carrier l5 and clamped After the potentiometer card has been clampedin place, the gage member 5! may be moved back to the position shown inFigs, 1 and 3 in which position the top edge of the potentiometer card,which is mounted on said carrier and engageable with the edge of saidcard for use in axially positioning said card in a predeterminedposition on the arcuate portion of said carrier and with its edgeparallel to the predetermined path of movement of said carrier, astationary optical inspection device mounted on said base adjacent saidpredetermined path for inspecting the card on said carrier, a capstanmounted on said base, a strand having its intermediate portionencircling and operatively engaging said capstan, means for connectingthe ends of said strand at Widely separated points to said carrier, andresilient means associated with said strand for maintaining said strandtaut and in operative engagement with said capstan whereby, uponrotation of said capstan, the strand is moved to rotate the carrierabout said axis, thereby to bring successive portions of the cardmounted on said carrier into the field of said optical inspectiondevice.

4. An inspection apparatus comprising a base, a carrier having anarcuate surface for supporting a potentiometer card in an arcuateposition thereon, a plurality of holding members mounted on said carrierfor holding said potentiometer card in said arcuate position on saidcarrier, a pivot support pivotally mounting said carrier on said base toturn about an axis concentric with saidarcuate surface whereby saidarcuate surface is guided through a predetermined path, a movable gagemember mounted on said carrier and engageable with an edge of said cardfor use in axially positioning said card in a predetermined position onthe arcuate surface of said carrier and With the edge of the cardparallel to the predetermined path of movement of said carrier, an armpivotally mounted on said carrier adjacent one edge thereof, an opticalinspection device mounted on said base adjacent said predetermined pathfor inspecting the card on said carrier, a capstan mounted on said base,a strand having its intermediate portion encircling and operativelyengaging said capstan and having one of its ends attached to saidpivoted arm and its other end attached to said carrier adjacent anotheredge thereof spaced from and opposite said one edge, and spring meansurging said arm for rotation in one direction to maintain said cord tautand in operative engagement with said capstan, said capstan beingrotatable to move said strand and said carrier and thereby bringsuccessive portions of the edge of the card mounted on the carrier intothe field of the optical inspection device.

5. An inspection apparatus comprising a base, a carrier having anarcuate portion for supporting a potentiometer card in arcuate positionthereon,

a plurality of clamping members mounted on said carrier for holding saidpotentiometer card in said arcuate position on said carrier, a pivotsupport for pivotally mounting said carrier on said base to turn aboutan axis concentric with said arcuate portion whereby said arcuateportion is guided through a predetermined path, an

optical inspection device mounted on said base.

adjacent to said predetermined path for use in inspecting said card, amember movably mounted on said carrier, a strand connected at one end tosaid movable member and at its other end to said carrier at a pointwidely separated from said one end, a capstan mounted on said base andencircled in operative engagement by the intermediate portion of saidstrand, and spring means tending to move said movable member to maintainsaid strand taut and in operative engagement with said capstan whereby,upon rotation of said capstan, the strand is moved to advance thecarrier and thereby move successive portions of the card mounted on thecarrier into the field of the optical inspection device.

6. An inspection apparatus comprising a base, a movable carrier having acard supporting surface thereon, holders on said carrier for holding apotentiometer card in position on said card supporting surface, meansmounting said carrier on said base for movement in a predetermined pathwhereby said card supporting surface is guided in a predetermined pathof movement, a stationary optical inspection device mounted on said baseadjacent the path of movement of said card supporting surface for use ininspecting a card on said carrier, a capstan mounted on said base, astrand having its intermediate portion encircling and operativelyengaging said capstan, means for connecting the ends of said strand atwidely separated points to said carrier, and resilient means associatedwith said strand for maintaining said strand taut and in operativeengagement with said capstan whereby, upon rotation of said capstan, thestrand is moved to advance the carrier and thereby move successiveportions of the card mounted on said carrier into the field of saidoptical inspection device.

JOHN S. STULL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Baker Oct. 31, 1944

